Insect repellent preparations



Patented Nov. 7, 1950 No Drawing. ApplicationDecember 5, 1946, SerialNo. 714,229

(Granted under the act of March 3, 1883, as

This invention relates to improved insect repellent preparations, moreparticularly to a repellent composition in emulsion form.

The present invention is a continuation in .part of prior application,Serial No. 612,117, filed August 22, 1945, now Patent No. 2,512,675,dated June 27, 1950, and Serial No. 620,384, filed October 4, 1945.

As described in prior application, Serial No. 612,117, it has been foundthat certain hydrogenated naphthols proved to be satisfactory repellentsfor insects and also that when certain specific naphthols were mixed indefinite proportions a marked synergism resulted.

Similarly, as described in prior application,

Serial No. 620,384, it was found that certain hydrogenated diphenylcompounds presented marked insect repellent activity and that mixturesof diphenyl compounds presented a greatly increased repellent activity.lVlany of these insect repellents are highly effective and only asmall'quantity need be applied. The application of a small quantity of aviscous liquid can best be in a liquid diluent or in the form of anaqueous emulsion. It was also pointed out in the co-pending applicationthat the addition of a carrier vehicle or diluent may profoundly affectthe activity of the repellent. In some cases this action is synergisticand in others it is antagonistic. There appears to be no a prioriconsiderations upon which a suitable carrier vehicle or diluent may bechosen. For example, as was pointed out in the prior application, commonvehicles such as ethyl alcohol, displayed a synergistic or antagonisticeffect even after the apparent evaporation of the alcohol from thesurface of the skin.

In many circumstances an emulsion is an eminently desirable vehicle forthe application of insect repellents to the surfaces to be protected.This is particularly true in the cosmetic field. Aqueous emulsions alsohave the advantage of being relatively non-inflammable and odorless.

It has been found as a result of considerable experimentation thatstable emulsions of these insect repellents may be produced withoutantagonistic effects upon the repellents. As a result of tests undersimulated tropical conditions it has been ascertained thatemulsion-repellent preparations containing only 50% of repellentchemicals were almost as effective as the pure repellent chemicals.Thus, it is apparent that with the proper choice of emulsifying agentsthe amended April 30, 1928; 370 0. G. 757) The following formulas aretypical preparations which have been found to be effective as insectrepellents: 1

Formula I I I l Cc. 2 phenyl cyclohexanol j }'35 2 cyclohexylcyclohexanol 1 5 Gum tragacanth 1% in aqueous solution 50 In producingthis emulsion the mixed repellent chemicals are added, slowly to theaqueous solution with constant stirring as, for example in a WaringBlender or other emulsifying apparatus. The product is an oil inwateremulsion which may be readily applied to the skin and is highlyeffective as an insect repellent.

Formula II 2 phenyl cyclohexanol ....0c.. 35 2 cyclohexyl cyclohexanolcc 15 Acacia gm 12 Water cc 50 The gum acacia is ground into the mixedrepellents and to this the water is slowly added with vigorousagitation. This procedure produced a stable water in oil emulsion whichis also highly effective as an insect repellent;

Formula. III

Co. 2 phenyl cyclohexanol 35 2 cyclohexyl cyclohexanol 15'Triethanolamine 5 Gum tragacanth in 1% aqueous solution 45 A wellstirred mixture of the aqueous solution of the tragacanth and thetriethanolamine is poured slowly and with vigorous agitation into therepellent mixture. This produces a stable emulsion containing effectiveinsect repellents.

The mixed repellents are added slowly and with vigorous agitation to thesolution of dimethoxy cellulose producing a stable effective emulsion.The above formula may be modified so as to impart in addition, effectivesun screen properties by adding a suitable screening agent such assodium salicylate in an amount of from about 2 to 5 percent of theaqueous phase.

Compositions of similar effectiveness may be produced according to theformula given above 3 utilizing the optimum mixtures of the hydrogenatednaphthols as set forth in application, Serial No. 612,117 andhydrogenated diphenyls as described in application, Serial No; 620,384.

Similarly, insect repellent emulsions may be made upby the sametechnique utilizing equivalent amounts, i. e., of the order of 50% moreor less of other repellent chemicals, for example effective insectrepellent emulsions may be'produced by utilizing 1,2 dihydronaphthaleneor 2 methoxy cyclohexanol in lieu of the repellent compositions inFormulas I to IV. Again, effective repellent compositions may beproduced by emulsifying a mixture of approximately 3' parts of 2 phenylcyclohexanol, 6 parts of 2 cyclohexyl cyclohexanol and 1 part ofhydrogenated vanillin in parts of water.

The protection afforded from these repellents is from 4 to 6 hours undersimulated tropical conditions of 90 F. dry bulb and 80 F; Wet-bulb. 1nactualtests in the tropics the-compositiondisplayed a repellency of from10 to 13 hours-against Aedes albz'manus. The effectiveness of theemulsions closely parallels that "of the repellent mixtilres describedin the earlier applications. Repellentemulsions "of thetype "describedare effective against 'Inosqu'rto'es, mites, chiggers, ants andcertain'fleas ZAswvill :be appreciated, emuisions maybe made up: forother than topical application, for ex amtple emulsions suitable forspraying may 'be produced according to the several methods "describedbust employing greater percentages of .Waten: 'If desired, wettingagents having no antagonistic effect on the repellent, such as aerosol,may be incorporated in the emulsion to improve its effectiveness.

i-fiThejnvention described herein may be :manufacturedand usedby or forthe Government of the IJnitedStates ofAmerica for governmental purposeswithout the: payment of any royalties thereon or therefor.

'Iclaimj, 7 "1;; .An fin's'jct "repellent composition comprising "amixture er 35 parts of 2 phenyl cyclohexanol and 15 parts of 2cyclohexyl cyclohexanol emulsified in 50 parts of water containing anemulsifying agent.

2. An insect repellent composition comprising a mixture of parts of 2phenyl cyclohexanol and 15 parts of 2 cyclohexyl cyclohexanol emulsifiedin 50 parts of an aqueous vehicle containing gum acacia.

3. An insect repellent composition comprising a mixture of 35 parts of 2phenyl cyclohexanol and 15 parts of 2 cyclohexyl cyclohexanol emulsifiedin '50 parts of aqueous gum tragacanth solution.

4. An insect repellent composition comprising a mixture of 35 parts of 2phenyl cyclohexanol and 15 parts of 2-cyclohexy1 cyclohexanol emulsifiedin parts of an aqueous solution of dimethoxy cellulose.

' MICHEL PIJOAN.

, REFERENCES CITED The following references are of record'in t he fileof this patent:

' UNITED STATES PATENTS Number Name .Date 1,755,178 Grant Apr.f22, 19301,842,993 Marx Jan. 26,1932 1,942,801 Britten 1 J an. 9, 1934 1,963,955Cleveland .June '26,, 1934 2,005,797 Moore June 25., 1935 2,073,683Christiansen Mar. 16, 1937 2,100,468 Brubaker et a1. Nov. 30, 19372,118,954 Thomas .May 31, 1938 2,125,310 Perkins Aug. 2, 1938 2,136,020Pirie Nov. 8,1938 2,396,013 Jones Mar. 5, 1946 FOREIGN PATENTS NumberCountry Date 1 28,059 fFrance- Jan. '14, 1925 1 (Addition to No.566,406.)- 505,426 Germany Sept.- 4,193!) 694,421

Germany Aug. 1, 1940

1. AN INSECT REPELLANT COMPOSITION COMPRISING A MIXTURE OF 35 PARTS OF 2PHENYL CYCLOHEXANOL AND 15 PARTS OF 2 CYCLOHEXYL CYCLOHEXANOL EMULSIFIEDIN 50 PARTS OF WATER CONTAINING AN EMULSIFYING AGENT.